In the prior art, as a first conventional technique, there is known a tube pump (Japanese Patent No. 3,109,015) as a fluid transporting device comprising: a holder having an inner circumference formed into a generally arcuate shape; a tube having an elasticity and held in the inner circumference; a rotary disc having a groove so shaped as to hold at least one roller for elastically deforming and closing one portion of the held area of the tube and that the roller can move, when rotated in one direction, to a position to close the tube and, when rotated in the other direction, to a position to keep an elastic state without closing the tube; and a rubber plate so disposed at a position for the roller to start the push of the tube as intersects with the revolution path of the roller.
As a second conventional technique, on the other hand, there is known an ink feed mechanism (JP-UM-A-59-61943) for an ink jet recording apparatus, comprising: at least one roller; placing means for placing a predetermined portion of a tube having an elasticity; and rotational radius varying means for rotating the roller around a center axis and for varying the radius of rotation of the roller in accordance with the rotating direction so that the roller may rotate around the center axis and so that the tube placed on the placing means may be pressed, when the roller rotates in a predetermined direction, but not when the roller rotates in the backward direction.
In the invention of the first prior art or the second prior art, however, the roller presses the tube directly thereby to feed the liquid. It is, therefore, thought that the liquid feeding portion (or the internal diameter of the tube) is varied as a result that the tube is stretched in the flow direction, thereby to make it difficult to keep the flow rate stably.
Moreover, the revolving direction of the roller to close the tube and the revolving direction to release the closure are determined to raise a problem that the direction to transport the fluid cannot be easily changed.
When the drive is interrupted while the roller being positioned to close the tube, moreover, it is thought that the roller is pushed back far away from the tube by the elastic force owned by the tube. In this case, there arises another problem that the closure of the tube is released to permit the leakage of the liquid.
The present invention has been conceived to solve the aforementioned problems, and contemplates to provide both a small fluid transporting device, which can rotate the rotary pressure mechanism forward and backward, which allows no leakage of the fluid even in the drive intermitting state and which can retain a stable fluid feeding rate, and a fluid transporter which is provided with that fluid transporting device.